DE1512369A1 - Device provided with a delay circuit - Google Patents

Description

Dipl.-Ing. ERICH E. WALTHER PHN. 1701

Applicant: NV PHILIPS '8LQBUHPENFABRIEKEII ^g

'IHE- 1701
June 6, 1967

"Device provided with a delay circuit."

The invention relates to a device which is provided with a delay circuit whose impedance between a first input terminal and a first output terminal is inductive and capacitive between the first input terminal un <3 of a second output terminal, while a second input terminal and a third

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Y§ ^t 12369

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Output terminal to earth.

It is known that such delay circuits for obtaining signals become bits an impulse function from signals with a step-shaped function is used. To this end can be from a stepped input signal delayed input signal can be subtracted, so that a pulse-shaped signal arises, whose Pulse duration depends on the delay time of the delay circuit. The differentiating effect of the capacitances in the Veyzögerungskreis a pulse-shaped current can be generated from a step-shaped input signal.

The invention creates a completely new application for such a » Delay circuit and the device according to the invention is characterized in that between of the first and second output terminals, respectively, and the third output terminal, means for converting Current are arranged in voltage, which, if the input terminals over the characteristic impedance of the delay circuit, a signal with a somewhat gradual puncture is performed, Create tensions, which are superimposed on each other via a phase inverter and then an overlay, supply tension with a more pronounced stepped puncture.

909826/1071 ^{The Erf> indun} e lie * ^ai "knowledge

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PHN.1701

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based on the *, v / enn a · »delay circle Signed with a somewhat stepped puncture) this signal through the application of the Combination of a one-time reflection and the current impulses in the capacities of the delayed network can be converted into a signal with a more pronounced stepped puncture, Z, B. for Radar * or Pernsehtwecke can «in signal with a more or less sinusoidal function to a signal with a somewhat stepped puncture Receive a signal with a more outstanding one stepped function are superimposed.

The device according to the invention can be used in particular for aperture correction of video signals. In a Fernaehaufnähmeröhre a sharp transition between different potentials in the potential image on the target of the electron beam scanning this plate is transmitted not as a sharply defined, but as a somewhat stepped puncture in the video signal emitted by the recording tube. This blurring is due to the fact that at the sharp transition on the target plate the finite cross-section of the electron beam encompasses the two potential values, so that a partially isolated image is defined in the video signal. It is known that through aperture correction of the video signal the approximately? stepped function into a more extensive

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convert shaped step-like function, which better reflects the 'BCharfen About narrowing in the potential image on the target plate of Fernsehaufnahmerb'hre. This was described in the article "Aperture compensation for television cameras" by RC Dennison »R.0.λ.-Review 14. Kara 1953, No. 1, pages 569-585.

The device according to the invention is used below, for example, on the basis of the bellie- ' Lowing drawings explained in more detail. Ss seigern

1 shows an embodiment of the device according to the invention, and

Fig. 2 is a diagram eur explanation of the operation of the device in question.

In Pig »1, 1 denotes a signal source which supplies a voltage with an approximately step-shaped function and in series with an Oleichipihnutifiequelle 2 supplying a bias voltage is switched. Source 1 can be a 2.8 »television camera that emits a video signal. The from The bias voltage supplied to source 2 is used »as follows from the description below, rum * Obtaining a suitable setting point« Inet transistor · »Bine terminal dir signal source 1 let Via a

eic »resistance 3, the value of which is equal to α em oharakteris-

*> table resistance of a delay circuit * 4 is, ο?

^ connected to a first input terminal 5 of circuit 4

• * 4. buna en. Sine little one who is GIe i cn eppanna source 2

• connected to a grounded second input gill 6. The delay circuit 4 has three output

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input terminals 7, 8 and 9. To obtain an inductive impedance between the first input terminal 5 and the first output terminal 7, some coils are connected in series in the circuit 4. The capacitive impedance between the first input terminal 5 and the second output terminal ü is formed by some capacitors. The output terminal 9 is connected to earth. In the deceleration ÖV: reis Xiet ^ n points, 10, 11 and 12, the Zv.-corner is described in more detail with reference to FIG. 2, among other things. According to one measure of the invention, point 1C is capacitively connected directly to earth. The output terminals 7 and 8 are at the emitters of transit gates 13 and 14 * whose bases are coupled to earth and whose collectors and 16 are connected via resistors 17 and 18 to a negative voltage terminal -V.

The equation source 2 yields Via the resistance 3 and the delay-tionefc rice 4 between the emitter and the base of the transistor 13 a voltage for obtaining a suitable Set point. The emitter is for the same purpose of the transistor 14 through a resistor 19 to a

connected to a positive voltage carrying terminal + V,

cd The emitter of a transistor 20, whose base with the collector 16 of the transistor 14 is connected, cn

^ is via a resistor 21, of which a changeable

o -

• sj rather part of a capacitor 22 is bridged, Bit connected to earth. The interconnected KoI-

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lectors of the transistors 13 and 20 one over a Coupling condenser 23 coupled with a lüerame 24. If the signal source 1 has an alarm with a something supplies step-shaped puncture, according to the principle of the invention at the clamp 24 appears a · Spannurg with a more pronounced step-shaped puncture,

The operation of the device according to the invention will now be based on the Pig. 2 explained. A voltage supplied by the signal source 1 with One of sth;> s stepped puncture is in Pig. 2a shown. This signal is used to operate the transistor 13 from the voltage source 2 of the same supplied preload superimposed. The curve 3 ^ places d-.e from the source 2 to the resistor 3 supplied potential, while curve 31 d ^ s Represents the overlap potential of sources 1 and 2. The somewhat gradual change between the two i'otentialen is more or less s chemical shown with curve 32. If the signal source 1 does not supply any voltage, the delay circuit 4 and the transit gate flow through the resistor 3f

to 13 a supplied by the DC voltage source 2 ο

® and the set point of the transistor 13 belonging α »direct current. This direct current makes one

- »Voltage drop across resistor 31 but not across the one to be regarded as almost idtal Circuit 4. The voltage drop across the input impedance

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The Tranfeietor »13 is chosen to be very low, so that the VirEÖgtrungskreis 4 is almost at ^r zero potential.

When the signal source 1 supplies the voltage shown in Fig. 2a, because the V / trt of the resistor 3 is equal to the characteristic resistance of the delay circuit 4, only half of the potential jump shown with the curve 32 is applied to the input terminals 5 and 6 placed. The circle 4, which is almost at zero potential and which is shown in Fig. 2 with curve 33, is then given di.s in Pig for terminal 5. 2b with curve 34. The potential jump that occurs is then planted in delay circle 4. It is assumed that after a period of time T the potential jump reaches point 1C. As shown in Pig Losses the potential at this point also with an equal jump to the value indicated by curve 34. If this method is used for points 11 and 12, FIGS. 2d and 2e result low thing: ngeIm ₁ edanE

of transistor 13 earthed (short-circuited) to

° is »εο from terminal 7 the positive point

J ^ tialsprung like a total jump in reverse

^ Judgment refined. D & bel h'at the Emitterstron des ^ Transistor 13 by the short circuit to l ^ rde one

~ * equals a point like that of signal source 1

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provided tension. Since the emitter current is approximately equal to the collector current, the pig occurs at point 15. 1 the potential jump shown in Fig. 2f. Infclge of the increase in the collector power of that Set point to the value achieved by the voltage supplied by signal source 1 then the potential at point 15 increases from the value indicated by curve 35 to the fourth indicated by curve 36. When Pig. 2a and 2f are compared with one another, it turns out that only through the effect of the transistor 13 at terminal 15 a potential occurs which is equal to, be it delayed, puncture as the voltage supplied by the signal source 1 has.

The reflected potential jump in

reverse direction achieved with a time delay T successively points 12, 11, 10 and -5, as in Piguren 2e, 2d, 2c and 2b with the sloping curve 37 shown iet. After chamfering the reflected potentials, the points are in contact again a potential that is almost zero and the bit of

> Curve 33 is shown. When the potentials ^ ration reaches resistor 3, in which it is completely absorbed, the voltage drop across resistor 3 is almost the same as that supplied by signal source 1 Tension.

In the above, the influence of the Potential jumps at points 5, 10, 11 and 12 the capacities associated with these points

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would disregard flowing currents. It is known that a voltage that changes more or less over time across a series connection of a capacitance C and a resistor R ensures that a current flows through this series connection which almost reaches the puncture _t .

Has. With a low value of the resistance R, the current has almost reached its constant value after a short time. If the voltage is kept constant after a more or less linear change, the current decreases again with the above-mentioned, but now negative, puncture. As a result of the inductances that are always present, the current has a more or less flowing course. Pur the first input terminal 5, whose potential jumps in Pig. 2b is represented by curves 38 and 39 in Pig. 2g this current is represented by the capacitance associated with this point 5. Current pulse 3 ° and 3 ' ³ generate a collector current via the low impedance of transistor 14 towards 2rde in resistor 18, and point 16 generates a current pulse 3S and 39

brings about the corresponding potential curve. Potency

tial jumps at points 11 and 12 result in

Similar manner to that also in Pig. 2g shown ^ current pulse ·. When these current pulses over-

° 1, they generate in the collector circuit of the Tran - "" * sistore 14 a collector current, which at point 16 a in Pig. 2h brings about potential curve.

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The curve 40 corresponds to the potential at point 16, which belongs to the KoIlektoratrom flowing at the setting point of the transit gate 14.

. If after a measure of the invention the point 10 is connected directly to earth via a capacitance, this point makes no contribution the emitter stream of the transit gate 14. The purpose of this Measurements are explained in more detail below.

The positive occurring at funct 16

By cutting off the transistor 20, the change in potential leads to a reduction in the collector current of this transistor. The thereby reduced voltage drop across the resistor 17 leads to a lower potential aa point 15. The extent of this reduction can be set according to a measure of the invention in that at least part of the resistor 21 alternates _{with the capacitor (22).}

is short-circuited in terms of current. If the Transistor 14 brought about a change in potential (Pig. 2h), the phase of which is reversed via transistor 20, the potential brought about by the transistor 13 (Pig. 2f) occurs at point 15 -or

co possibly at Klenrne 24- that in Pig. 2 j dar-

Φ posed potential. E · turns out that

£ J dsβ in Pig. 2a signal shown with a something

^ step-shaped puncture using the device

<j according to the invention in a in Pig. 2j shown

Signal with a more pronounced step-shaped

Puncture is converted.

Pur den in i'ig. 2a shown potential jump 41, the method already described for the potential jump 32 applies.

According to one measure of the invention, the shape of the with the help of the capacities is derived from the corrective signal derived Signe.la determined by being at a certain point in the delay circuit 4 a direct capacitive coupling is applied between the first input terminal and earth. As a result, the potential error delivers; -n directly to the Earth connected point of the delay circles 4 none Contribution to the emitter current of transistor 14. From Pig. 2h can be clearly seen that the Choice di ·. es point d-s received derived Signsl can be influenced in a simple · way.

Especially * when using the device for aperture correction of a video signal, it is desirable that a derived signal with a local short-term subsidence is formed. A signal with a somewhat stepped puncture k inn then be overcomed without rU-fr ·! - · * ": * if; L resulting Outline is too sharp and therefore annoying. (Con-

co tour enhancement).

κ »Ss 2 appears-'t,

the delay

circuit 4 is made up of both coils and capacitors Circuit .Is cloth included a piece of coaxial cable can. In the latter case, however, should be Application of a direct capacitive coupling of the

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Sheath of the cable be interrupted.

It is also evident that to maintain the setting of the transit gates 13 and 14 the base is placed on a heating clamp and by means of a large blocking capacitor can be isolated from earth. The blocking capacitor then connects the base in an interchangeable manner with earth.

A.usserdera it makes sense that the choice of ρηρ or npn transistors with the associated DC voltages for the principle of the invention is not essential.

Tubes can also be used instead of translators. Instead of transistors 13 and 14 two tubes must then be used, their control grid are grounded and their cathodes are connected to terminals 7 and 8, respectively. Using Negative feedback can be ensured that the listening posture has a sufficiently low input in the - »edanz Has. The transit gate 20 can also be replaced by a tube, the control grid of which is marked with point 16 and whose anode is connected to point 15.

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Claims (5)

1J device which is provided with a delay circuit whose'impedance between a first Singangskleiame and a first output terminal inductively and between the first input terminal and a second output terminal is capacitive, while a second input terminal and a third output terminal connected to earth, characterized that between the first or the second output terminal and the third output terminal Means for converting current into voltage are disordered when the input terminals are on the characteristic Impedance of the delay circuit is fed a signal with a somewhat stepped puncture will generate voltages which, if they are superimposed on one another via a phase inverter, a Overlay voltage with a more pronounced deliver stepped puncture. 2. Apparatus according to claim 1, characterized in that the delay circuit is provided with a capacitive coupling between the first input terminal and earth. CD 3. Device according to claim 1 or 2, characterized in that the first and the second output terminal ca to the emitter of a first - »or second transistor is connected, whose bases ο - ° are coupled to earth and their collectors over Resistors are connected to a voltage-carrying terminal, the collector of the first or the second transistor rait the collector or the bagie A third transistor is connected, the emitter of which is connected to earth via an impedance. 4 ·. Apparatus according to claim 31 thereby marked, 'that the impedance in the Emitterlcreie of the third transistor consists of a resistor, at least part of which is bridged by a condenser gate. 5. Device according to one of the preceding claims for aperture correction of a video signal. 6, television camera, which is equipped with a device according to one of the preceding claims 'see is. BAD ORiQSNAL 909826/1071 .AS blank page